This invention relates to bushing mountings for tool guide jigs, and more particularly relates to a bushing mounting assembly for use with a variety of tool bushings.
Tool guide jigs are usually in the form of plates with holes machined or cast in place for acceptance of liners for use with tool guide bushings. Tool guide jigs are used for production line manufacture of many parts assuring accurate placement of holes in a proper pattern. Further, each of the bushing liners permits quick and easy removal and replacement of a tool guide bushing when it becomes worn or damaged. These bushings are designated in the art as "renewable bushings." Also, if several different operations are performed with different size tools, it may be necessary to change the bushings to accommodate different size tools.
In the manufacture of these jigs, such as metal jigs, the holes for placement of the bushing liner can be provided in the manufacturing of the jigs and bushings, then press fitted into the holes. However, where the jig is to be used on uneven or contoured surfaces, the liners must be cast in place. For this purpose, the bushing liner must be positioned with extreme accuracy and then the jig cast around it. For liners used with a threaded sleeve and locking screw, the relative position of the liner and the locking screw sleeve is extremely difficult to maintain. Thus, when the jig is being cast, movement of the liner or sleeve with respect to each other may result in a jig which is unusable.